Nursing Elites

1. Which statement is untrue?

• A. RNA is single-stranded.
• B. RNA contains uracil.
• C. DNA codes for proteins.
• D. DNA cannot be altered.

Correct answer: D

Rationale: DNA can be altered through various processes such as mutations, genetic engineering, and epigenetic modifications. Changes in DNA can occur naturally or through external influences, leading to variations in the genetic code. Therefore, the statement that DNA cannot be altered is untrue. Choices A, B, and C are true statements. RNA is indeed single-stranded, RNA contains uracil instead of thymine, and DNA serves as a template for protein synthesis.

2. What is the purpose of phloem tissue in plant stems?

• A. It conducts water up through the stem.
• B. It conducts the energy of light to leaves.
• C. It conducts food throughout the plant.
• D. It conducts carbon dioxide throughout the plant.

Correct answer: C

Rationale: The purpose of phloem tissue in plant stems is to conduct food, particularly sugars produced in the leaves during photosynthesis, throughout the plant. The phloem transports these organic compounds to various parts of the plant where they are needed for growth and energy. Choice A is incorrect because water is primarily transported by xylem tissue, not phloem. Choice B is incorrect as the energy of light is captured by chlorophyll in the process of photosynthesis, not conducted by phloem. Choice D is incorrect because carbon dioxide is mainly absorbed through the leaves and transported to other parts of the plant through diffusion, not by phloem.

3. What is the function of water in photosynthesis?

• A. Combine with carbon dioxide
• B. Absorb light energy
• C. Supply electrons in the light reactions
• D. Transport hydrogen ions in the dark reactions

Correct answer: C

Rationale: The correct answer is C: 'Supply electrons in the light reactions.' In photosynthesis, water is split during the light reactions of photosynthesis, releasing electrons that are used in the formation of ATP and NADPH, crucial for the synthesis of glucose. Choice A is incorrect because water does not combine with carbon dioxide in photosynthesis. Choice B is incorrect as water does not absorb light energy directly. Choice D is incorrect because the transportation of hydrogen ions mainly occurs in the electron transport chain, which is part of the light reactions, not the dark reactions.

4. Which of the following organelles is responsible for producing ATP in cells?

• A. Nucleus
• B. Mitochondrion
• C. Chloroplast
• D. Lysosome

Correct answer: B

Rationale: The correct answer is 'Mitochondrion.' Mitochondria are known as the powerhouse of the cell and are responsible for producing ATP, the energy currency of the cell. The nucleus is responsible for storing genetic material and controlling cell activities, not for ATP production. Chloroplasts are found in plant cells and are responsible for photosynthesis, not ATP production. Lysosomes are involved in digestion and waste removal, not ATP production.

5. Where is the genetic code for each person stored?

• A. RNA
• B. DNA
• C. Nucleus
• D. Chromosomes

Correct answer: B

Rationale: The genetic code for each person is stored in DNA. DNA carries all the hereditary information, including unique traits and characteristics. RNA (Choice A) is involved in protein synthesis but does not hold the complete genetic code. The nucleus (Choice C) is a cellular organelle that houses the DNA, but it is not the genetic code itself. Chromosomes (Choice D) are structures made of DNA and proteins, but the genetic code is specifically encoded in the DNA molecule.

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